UNIX Shell循环控制—while
while循环，语法如下：
.../shell/iftest>lfelif.sh ifeditor.sh ifparam.sh ifwr.shgrepif.sh ifelif.sh ifpwd.sh if1.sh*ifcounter.sh ifels.sh ifroot.sh if2.shifcp.sh ifinteractive.sh ifset.shifcp2.sh ifmkdir.sh iftest2.shifdirec.sh ifmkdir2.sh iftst.sh*--the end--
